Stereocamera film and shutter wind



July 19, 1949. A. J. BACHELDER 2,476,576

` STEREO CAMERA FILM AND SHUTTER WIND Filed April 19, 1946 2 Sheets-Sheet 1 UDDEDEDD!!UUDDUDDDDDDUDDUEDDIJUDDUBDDDUDGUDDDEDDUEUUDUUUUUDDDCIDD 2 Sheets-Sheet 2 A. J. BACHELDER STEREO CAMERA FILM AND SHUTTER WIND July 19, 1949.

Filed April 19, 1946 Wav/2cm, /Mrwm Patented July 19, 1949 STEREOCAMERA FILM AND SHUTTER WIND Albert J. Bachelder, Lexington, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a

corporation of Delaware Application April 19, 1946, Serial No. 663,542

4 Claims.

The present invention is concerned with improvements in the structure and operating mechanism and characteristics of photographic devices. The arrangement is of particular advantage in stereoscopic cameras, and the invention is specifically illustrated in connection with such a device, although, as will appear, many features are capable of application to cameras of different types and to devices in general employed in taking or exposing of photographic images.

The invention provides a relatively simple and economical design for a high quality camera. This results largely from the manner in which the various operating parts and functions are related one to the other. A particular feature is in the novel manner in which a single manually operable element serves the several functions of cooking the shutter, drawing the film across the framing plate and winding it on the takeup spool and, through an associated automatic stop means, measuring olf the iilm to locate properly the appropriate nlm frames over the exposure apertures. Because of the desirability of spacing the frames of a given pair of stereoscopic images by one or more intervening frames on a lm to preserve the inter-ocular distance and at the same time utilize all of the frames on the film, it is necessary that the iilm be advanced unequal distances for successive exposures. On the other hand, the cooking of the shutter each time is substantially a fixed cycle. The arrangement here provided nevertheless enables both these functions of cooking the shutter and advancing the film the different distances to be performed from a single manually operable member.

The mechanism includes a rotary shutter provided with angularly spaced openings adapted to control simultaneously the two exposure apertures, the shutter having associated therewith spring tensioning means therefor constrained between the shutter and a rotary follow-up drum. Upon release, the shutter is advanced a predetermined angle through an exposure position, and re-cocking or re-tensioning of the spring is effected by advancing the drum an equal angle following eachexposure. .Both the shutter and the drum advance successively in the same direction, and no reverse movement of the shutter is required in the cooking operation. The successive advances of the spring restraining means are achieved through novel operating means which includes a concentrically mounted oscillatable drum. Although the movements of the shutter comprise a progressive step-by-step advance in the same rotary direction,- the spring tension thereon for each operation is nevertheless uniform for any given setting of shutter speed or exposure time interval.

The invention is further characterized by a structural and functional association of certain elements for adjusting the shutter speed. The shutter embodies two plate sections provided with concentric coaxial stem parts extending to exteriorly of the camera. By the arrangement provided, relative angular adjustment between these coaxial elements effects not only an angular adjustment of the shutter disks and thereby an adjustment of the shutter openings, but also an adjustment of the tension of the shutter operating spring. The lesser the effective opening, the greater the tension, and conversely. The result is a wide range of selectable time intervals for so-calied automatic instantaneous exposures.

An important feature of the invention resides in the combination of the above described principles and relation of elements in a rotary shutter for stereoscopic cameras wherein simultaneous shutter operation occurs at both apertures. The substantially integral relationship of both portions of the shutter ensures the same operation at the same time at both apertures, and ad justments affect each in the same manner.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplied in the construction hereinafter set forth, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. l is a rear view of the camera with the rear plate removed and portions of the casing partitions broken away;

Fig. 2 is a top plan view with the casing broken awa/y;

Fig. 3 is a section of the film illustrating the location and spacing of the pairs of images;

Fig. 4 is a fragmentary sectional View taken through the axis of the shutter mechanism;

Fig. 5 is a front end view of the shutter adjusting mechanism;

Fig. 6 is a top plan view looking down on the counter dial of Fig. 1;

Fig. '7 is a cross-sectional view taken on the line 1-1 of Fig. 4;

Fig. 8 is a similar view through the spring drum taken on the line 8-8 of Fig. 4;

Y Fig. 9 is a similar cross-sectional view through the shutter spring tensioning drum taken on the line 9 9 of Fig. 4; and

Fig. 10 is a detail view of the shutter release trigger of Fig. 2 but looking from the reverse side.

The stereoscopic camera embodying the invention includes a main casing lll provided with a rear cover plate and appropriate inner partitions. A pair of lens mounts |`2 'contain suitable lenses adapted to transmit a pair of stereoscopic images to a continuous strip roll type film I 3, the film supply cartridge being 'shown at |4 and the takeup spool at l5. Mounted within the casing is a framing plate |6 having .spaced framing apertures |1. The axes of the lens mounts l2 and the framing plate apertures lI1 Aare spaced by the chosen inter-ocular distance. Forwardly of the 'framing plate 'IB is' mounted 'a rotary shutter means comprising a rear shutter disk 18 and a front shutter disk i9. The two lshutter `disks normally rotate together but may beangularly adjusted with `respect to each other jto'vary lthe effective exposure openings 2B there- "in in a manner to be later described in more .detai-l. Y

The lm' proceeds from the 'supply cartridge '14' along a suitably Aprovided channel at the rear of framing plate IS, over double sprocket 2|, to Athe takeup spool 1-5, which has a slot |5a to receive the leadingV end. Suitable pressure pad rolls and guides may be provided for the film, the details of which invention and are omitted from the drawings in the interest of clarity. The camera will preferably embody a viewfinder, an aperture therefor being shown at 22, Ain Fig. v1. The camera nor- 'nially will also embody various necessary toillustrate in the present case.

K The means for advancing the l'llm will now be described. The yupper end of `the shaft carrying "the takeup Vspool VI5 is provided with a squared end 3l! or other suitable splined construction, adapted to receive the manually operable knob 3| .whereby the knob is slidable thereon vbut capable of rotating the takeup spool l5. The measuring sprocket 2| is provided with the usual teeth 'engaging in marginal -ho'lesof the lm in accordance with standard construction. 'Rotation of the knob 3|, and advance fof the `iilm over the sprocket 2|, causes'the rota-tion of vgear 32 secured to the upper Aend of the sprocket shaft.

Meshing with gear 32 is a control gear 33, and 1 a' gear 34 in turn meshes 'with gear 33, the shaft to-which gear 34 'is secured having frctionaly Secured lon theupper end thereof a lcounter dial 35, 4to be later described in more detail,

I f The knob 31 is adapted in its rotation to per- .'fo'rm the three functions of advancing the film across the framing plate and'positioning it with the frames in proper position for exposure, winding the nlm on the takeup spool |55, and cooking the rotary shutter means. The knob 3| normally occupies the outer position shown in Fig. 1. Assuming that aliilm has been threaded in the 'camera and the first stereo pair of film frames have been exposed, to set the camera for the next exposure the knob 3| is iirst depressed downwardly against the force of spring 36, the

vspring being coni-ined between a plate '31, rigid with the knob 3|, and a collar38 secured on the takeup spool shaft part is a lever 4| having an unstanding finger form no part of the present other de'ta'ils unsprocket shaft, but is adapted to be clutched vsecured yto the film :sprocket shaft.

Pivoted at Vv4|) to a casing itis -noted that drum 56 is r able means such as the spring 58.

thereto. In'the vspeciiic form shown, the clutch comprises complementary spline parts, one of which is integral with the drum 44, and the other Depression of the knob 3| rocks the lever 4| and, through the connected linkage, rocks the lever 43 clockwise, in Fig. 1permitt`ing the drum 44 to move upwardly under the pressure of a spring 46, causing engagement of the clutch.

Depression of the knob 31 and its plate 31 'serves also to rock a lever 50 pivoted in the casing at 5|, the lever having a finger engaging the undersunface'of the :plate 3:1, and a finger .52 on the oppcsiteend Inormally 'on the path of pins 513 and 54a, secured tothe Aupper surface lof the Ygear J33. Rocking of the lever swings the 'tinger' however, out of thevpath :of these pins. Assuming a rllmhas fbeen threaded through the camera and 'in :position to Abe wound on `spool |-5 .as will later AbeY described, and assuming that the knob -34 has been depressed, the knob is Vinitially given a'slight rotationuin the clockwise direction, in Fig. v2, which advances the iilm a small distance, rotating the sprocket 2| Aand thereby the gears 32 and 33 through Aa small angle, whereby the pin 54 passes slightly beyond the end of the lm :stop yarm 50. Simultaneously, the drum 44, having -been clutched tothe sprocket shaft 2|, is rotated a corresponding angle, winding ashutter-.cooking `cable 55 thereon. The opposite lend of oablef55 `is fc'onnected'to rotate a drum `coaxial with .the 'sh-utter vand thereby through a vpawl to rotate a second coaxial ldrum '56, which serves :to increasethe tension Ion the shutter operating spring. The details `of this mechanism and operl:ation will be 'later described, but yfor the moment provided with ya pair oi notches 51 adapted alternately to receive the lug v43a on :lever 43 which serves 4to lock the drum '55 in the vcorresponding positions. Lug 43a having been withdrawn from locking notch 51 in shutter spring drum 56, the slight initial rotation of vthe drum by the withdrawal of cable 55, and operation of mechanism to be described, advances the drum 'suiiiciently Iso that the lug 43a now rides von the surface of the drum.

The hand knob 3| isnow'permitte'd to move to its outer position under 'the urge of spring 35, and is then further rotated in the same yclockwise direction to lcomplete the operations of advancing the film to itsV next position and the cocking of the shutter mechanism. Rotation of the knob 3| continues until the next pin 54a on gear 33 engages the ilm stop lever 5B. This occurs 1by :reason 'of Athe fact that the lever 50 has been returned to the @position shown in Fig. 1, by suit- 'I'he film has now been advanced one frame and the shutter ycocked through certain mechanisms, the details of which will be further explained. For the time being it is noted', however, that lug 43a on the shutter lock lever has engaged in the next notch 51 of the shutt-er spring drum 5B under the action of a spring 59 which dominates the force oi' spring 45 located under the cable drum 44, permitting downward movement of drum 44 and disengagement of clutch 45, This is timed to occur simultaneously with, or preferably a little in advance of, the stopping of the film feed.

After exposure of the iilm in this position, upon the next advance of the film through the means thus far described, the film will be advanced a distance of three frames until the pin 54 again comes into engagement with the iilm stop arm in the position shown in Fig. 1. For this purpose, the pins 54 and 54a are spaced apart distances of 90 and 270, respectively. It should be observed, however, that the cooking of the shutter was fully effected within the initial portion of the rotation of knob 3| which advanced the film a distance of one frame or a little less.

The arrangement of the pairs of images on the lm will be later described, but for the present it may be noted that, assuming a standard 35 mm. film, the lm frames of a given pair of stereoscopic images will be spaced by one intervening frame.

The details of the shutter mechanism will now be described. As shown particularly in Fig, 4, projecting axially from the front shutter plate I9 and rigid therewith is a stem-like sleeve 60; and located concentrically therein is a stem 6I secured to the rear shutter plate I8. The main spring drum 56 is concentrically mounted about the sleeve 60. In the middle enlarged portion of drum 56 is located -a main spring 63, the outer end of which is secured to the drum 56 and the inner end to the sleeve 60, as shown particularly in Fig. 8. The drum 56 has a lower cylindrical portion 64 of reduced diameter, about which is mounted the oscillatory cable drum 65 upon which is wound one end of `cable heretofore described.

The cable drum carries a pawl 66 adapted to engage in the notches 62 located 180 apart in the periphery of the lower portion 64 of the main drum 56. The winding up of the cable 55 on the drum 44 in the manner heretofore described rotates the drum in a clockwise direction, in Fig. 9, advancing it substantially 180 and correspondingly advancing the spring drum 56 a like angle, through the action of pawl L66. The drum 56 embodies an upper sleeve portion in which are located the notches 51 heretofore described. There are two of these notches spaced 180 apart, and when the drum has been advanced a sumcient distance, the lug 43a on the locking arm 43 engages in the next notch 51, holding the drum in the advanced shutter cocked position. As also heretofore explained, the spring 59 urging the lever in a counter-clockwise direction, in Fig. l, is of sufficient strength to overpower the effect of spring 46 on drum 44, and the drum is forced downwardly, disengaging clutch 45. The drum 65 has connected thereto a coil spring 61, acting to return it in a counter-clockwise direction, in Fig. 9, to restore it to the position shown in this figure. For this purpose, one end of the spring is connected to a pin 68 iixed to the drum and the other end to a pin 69 xed in a casing part. This operation occurs when the lever 43 engages in a notch 51, de-clutching drum 44 from the film sprocket 2I. In the return rotation of drum 65, the cable 55 is withdrawn from drum 44 and rewound on drum 65. The return rotation is limited by a finger 10 on the periphery of the drum engaging a fixed stop 10a as shown particularly in Fig. 9.

The rotary shutter is now under the increased tension of spring 63 but is restrained in cocked position by a latch 1| pivoted in the frame at -12 and normally urged in a clockwise direction, `as shown in Fig. l, by a coil spring 13. In the cocked position, a finger 1I a on lever 1I engages in a notch 14 in the peripheral edge of the rear shutter plate I8, there being two of these notches 180 apart. Assuming the shutter mechanism has been cocked or placed under increased tension, as heretofore described, through the medium of spring 63, for an exposure, the button 15 is momentarily depressed against the force of spring 16, causing a cam means on the lower end of the button stem 15a to engage against a pin 1lb, on the latch 1I, rocking it counterclockwise, and releasing lug 1Ia, permitting the shutter mechanism to rotate in a clockwise direction, as shown in Fig. l, for 180 until the next notch 14 in the shutter plate I8 moves into position to receive the lug 1Ia.

The cam means carried by trigger stem 15a ls shown better in the reverse view of Fig. 10. A cam 11 is pivoted at 11a on plate 18. In the downward movement of plate 18 and cam 11, pin 1lb rides along the right-hand side of the cam, in Fig. 10, until the cam passes beyond it and permits the pin 1lb to snap to the left under the pressure of spring 13. In the meantime, lever 1I, in Fig. 1, has rst been rocked counterclockwise, releasing lug 1Ia from the shutter notch 14, and then returned clockwise to engage the next notch 14. This operation ensures against the shutter rotating more than 180 in the event that the operator holds the button 15 depressed for more than the necessary instant. Upon release of button 15 to its upper position, cam 11 may temporarily be forced counterclockwise, in Fig 10, by pin 1Ib, permitting the parts to assume the position there shown wherein the lower end of cam 11 will catch pin 1lb and force it in the shutter releasing direction when button 15 is next depressed. Cam 11 is normally held against pin 18a on plate 18 by spring 19. It will be understood that cam 11 has sufficient width, that is in the direction perpendicular to the paper in Fig. l0, so that pin 1Ib will pass along the back edge of the cam without interference with pin 18a or spring 19. The mechanism may embody other features not necessary to illustrate here, such as an interlock to prevent a second operation of the shutter by depression of button 15 until exposed frames have been advanced from their framed positions.

Certain features in the relation of shutter disk I8 and the locking lug 1Ia on lever 1I will now be described. The disk is generally of uniform radius, but adjacent the notches 14 the radius is enlarged at I8a so that, as the disk in its rotation nears a locked position, its periphery at I8a rubs against the lug 1Ia to brake the speed. The radius at the portion I 8b at the opposite side of notch 14 is of still greater radius so as to ensure that the rear face of notch 14 will engage lug 1Ia and positively stop the disk I8 at the desired position. A fixed pin 1Ic limits the inward movement of the lower end of the lever 1I so that beyond the areas I8a and I8b the disk I8 rotates free of contact with the lug 1Ia on the lever and avoids any drag on the disk while it is rotating through an exposure position.

It is noted that the two rotary shutter sections I8 and I9, and their integral parts 6I and 60, respectively, are locked together so as to rotate in unison. The angular locked positions of the plates I8 and I9 relative to each other may be adjusted, however, to vary the extent of the exposure openings 20. Each plate is provided with a pair of segmental exposure openings, but angular movement of the one with respect to the andere 7 other causes` a. -bilan-king oir' of' a eorrespending-` seotionof the openings in the latter. 'lhis ad@ ustment andv lockingl of the two sections in. selected position may be effected through the medium-oi an annular member 8l! (see. Fig. 4)L having an inner sleeve portion slidable in the sleeve 5U, but restrained from rotation with respect thereto by a pin 8'I fixed in the member 8U and! slidabl'e in a slot 82 in; the sleeve 6D. The upper end of the stem BIS secured tothe linner shutter plate I8 is provided with a nger 83 adapted to be received in. a. series of openings 84 inthe. upper surface (in Fig.. 4) of the. member 8U. For relative adjustment of the two shutter sections, the member 80- is depressed against spring 85 from engagement with the -nger 83 and then rotated, which serves to rotate the sleeve Gil and the forward shutter plate t9; with respect to the plate I8, to a selected angle, and then permitted to move outwardly for engagement of the finger 83 in an opening 84,. corresponchng to the desired adjustment. Rotation ci the disk I9 in a conn-.- ter-clockwise direction, in. Fig. 1, to reduce the extent of the exposure opening, simultaneously rotatesthe sleeve 60 in a counter-clockwise direction, in Fig. 8., serving to` increase the tension on the shutter .actuating spring 63. Such an adjustment effects a double function in that, simultaneously with the reduction of the extent of effective exposure opening in the shutter, it serves to increase the tension of main spring 6'3 so that the speed of the shutter is proportionately increased. In other words,l the device operates to ensure faster shutter action, as the shutter openings become smaller. The outer surface of Ythe sleeve member 8'0k is provided with appropriate indicia 861 to indicateI the net value of the time setting. Although the. tension ofthe shutter spring may be adjusted,l it should be noted that for any selected adjustment the tensioning each time is of uniform degree.

As heretofore described, the film is. advanced alternately one space and three spaces. Using 'a 35 mm. lm, the arrangement of -the stereo 4pairs of frames on the lm will be as indicated bythe brackets in Fig. 3;k That is, the respective frames of a given pair will be separated by one frame of another pair, and the succession of frames will be as illustrated in this figure. The arrangement is such that the lmhas no blank frames and the images of' a given pair are separated by a suitable inter-ocular distance. This result is accomplished without the use of any auxiliary reii'ecting surfaces, or the need of' carrying the lm. through a circuitous path.

Fig. 1 shows a construction. whereby the dial v35 is caused normally to rotate with gear 323 and its shaft BT but enables. manual rotation ofy the dial independently of its shaft and gear 34 to p0- sition it correctly with respect to an index or pointer 88'. 'The upper end of shaft 8T has sefcure'd thereon a washer 83; and located between 'the washer and dial 35 is a leaf type springy 9.0 which frictionally holds the dial to rotate with theshaft. v

As heretofore described, the. nlm counter 35 is 'directly connected to the iilm control gear 33'. It will. be noted, however, that the successive expo.- 'sure numbers do not immediately follow each othf er in order. In Fig. 6 the dial 35 isv at the No.v l exposure position corresponding to the No. 1 frames in Fig. 3. In the next advanceof the lm, the control gear 33 will move 90 and the counter dial 35 will be advanced tl'irouglr` a certain an- El'e dependent upon the gear ratio, to bring the No; 2 exposure position on the dial 3.5 opposite the index 88, and, upon the succeeding advance et the lm and rotation of the control gear 33 2165*, the dial 35 will be advanced to: bring. the No. err` posure opposite the index.

The operation of initially threading the lmin the camera will vary somewhat', depending on the particular details of construction, but inthe spe'- ciiic form shown it may be eiected in substantially the following manner. Itv will be assumed that the back cover has been removed and a earLv tri'dge i4 been inserted, but thelead: end ofthe film not threaded'. The sprocket 2l is' rotated in a clockwise direction (as viewedv in Fig.. 2') by graspingit directly with the fingers until 'd2' engages either stop pin 54 or 54a. The: position of dial 35 is then noted; that is,.wh1`ch numeA beri thereof is at the index 88'. Finger 52 is then released by depressing the knob 31' and rotationof the sprocket continued until the previouslyene gaged stop pin passes the iinger 52 whereupon knob 3l. is released and rotation of the sprocket continued. Note is taken at dial' 351V whether the stop gear 33 has been rotated 90 or 2.70"' when finger 52 next engages: aV stop' pin. Correct rotation of. the dial should have beenY 2709# for threading purposes. Ii.. however, it has been rotated but 90 tothe point ci engagement oi finger and stop pin, then ringer 52- is` rel-eased. by means or' knob 3l and further rotation of the sprocket continued until the ngernext' meets a stop pini which operation will be observed to have rotated the control gear 33 270.. The nlm is` then threade ed by inserting the lm leader in-y the slot te' of the spool t5, the back cover plate is restored. and the lmis then advanced byv turning knob 3lso that control gear 33 rotates 360". To accomplish this.. knob 3i. is turned untilv iin-ger 5-2 meets; one of the stop pins. The shutter release button 'E5 is then depressed, following which knot 3W is de.- pressed so that finger 52 may passa the stop pin, and knob 3i their released and rotation thereo continued untilv finger 52' engages the next' stop pin. At this point the nlm hasA been properly po-A sitironedv for' they initial exposure and' the shutter spring has been tensioned for' its operation. lr-y nally, dial 35 is manually set with the No.. 1 expoe sure opposite index` 88'.

After the iilm has been completely exposectit may be returned to the nlm cartridge M by roe tation of the knob la in conventional manner; In this respect it will be noted that the reverse sides of the pins 54 and 54u: or the reverse.` side of finger 52, or both, are provided with. an inclined surface soA that lever 5G' will be auto maticall-y cammed out of position, permitting iii-'ee reverse rotation of the control gearv 33 and crinel nected' gears.

Since certain changes may be made the above construction and dii-Terentembodiments of the invention could be made without departing from the scope thereof, it is intended that. all 'matter contain-ed in the above description or shown in the accompanying drawing shall'- beine terpreted' asi illustrative and not in a limiting sense.

Having described my invention, whatl claim as new and desire to-secure by Letters Patent is:

I. In a camera, in combination, a shutter mechanism, means for exposing frames of a photosensitiveI strip nlm, rotatable means for advancing said lm including an axially sli'dabile, manually operable element, a clutch compris ing a rotatable driven member and' a rotatable 'driving member, means for rotating said driving member in response to advancement of said film, spring means for holding said driven member normally out of engagement with said driving member, means responsive to axial movement of said manually operable film-advancing element for causing engagement of said clutch members, means responsive to rotation of said driven clutch member for cooking said shutter, means for insuring engagement of said clutch members after iilm advancement has commenced and irrespective of the axial position of said manually operable nlm-advancing member, and means for causing said clutch members to disengage when said shutter is cocked.

2. In a camera, in combination, a shutter mechanism, means for exposing frames of a phctosensitive strip film, rotatable means for advancing said film including an axially slidable, manually operable element, a film-metering device, means responsive to advancement of said film for actuating said metering device, a plurality of stops carried by said last-mentioned means, means cooperating with said stops and responsive to the axial position of said slidable, manually operable element for limiting the extent of film advancement between each exposure, a clutch comprising a rotatable driven member and a rotatable driving member and a rotatable driving member, means for rotating said driving member in response to advancement of said film, spring means for holding said driven member normally out of engagement with said driving member, means responsive to axial movement of said manually operable nlm-advancing element for causing engagement of said clutch members, means responsive to rotation of said driven clutch member for cooking said shutter, means for insuring engagement of said 4clutch members after film advancement has commenced and irrespective of the axial position of said manually operable film-advancing member, and means for causing said clutch members to disengage when said shutter is cocked.

3. In a camera, in combination, a shutter mechanism, means for exposing frames of a. photosensitive strip film, rotatable means for advancing said film including an axially slidable, manually operable element, means for limiting the advancement of film between successive exposures comprising a plurality of stops, an element adapted to be moved into and out of the path of movement of said stops in response to changes in the axial position of said manually operable element and means for moving said stops along a predetermined path in response to advancement of said film, a clutch comprising a rotatable driven member and a rotatable driving member, means for rotating said driving member in response to advancement of said film, spring means for holding said driven member normally out of engagement with said driving member, means responsive to axial movement of said manually operable film-advancing element for causing engagement of said clutch members, means responsive to rotation of said driven clutch member for cooking said shutter, means for insuring engagement of said clutch members after film advancement has commenced and irrespective of the axial position of said manually operable nlm-advancing member, and means for causing said clutch members to disengage when said shutter is cocked.

4. In a camera, in combination, a shutter mechanism, means for exposing frames of a. photosensitive strip film, rotatable means for advancing said film including an axially slidable, manually operable element, means comprising a plurality of stops and an element movable in response to changes in the axial position of said manually operable element and cooperating with said stops to differently limit advancement of said film after each of any two successive exposures, a clutch comprising a rotatable driven member and a rotatable driving member, means for rotating said driving member in response to advancement of said iilm, spring means for holding said driven member normally out of engagement with said driving member, means responsive to axial movement of said manually operable film-advancing element for causing engagement of said clutch members, means responsive to rotation of said driven clutch member for cooking said shutter, means for insuring engagement of said clutch members after lm advancement has commenced and irrespective of the axial position of said manually operable filmadvancing member, and means for causing said clutch members to disengage When said shutter is cocked.

ALBERT J. BACHELDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent N o. 2,476,576 July 19, 1949 ALBERT J. BACHELDER It is hereby certified that error appears in the printed specrfcation of the above numbered patent requiring correction as follows:

[SEAL] THOMAS F. MURPHY,

Assistant UOmmz'ssz'oner of Patents.

Certificate of Correction Patent N o. 2,476,576 July 19, 1949 ALBERT J. BAOHELDER It is hereby certified that error appears in the printed speclication of the above numbered patent requiring correction as follows:

Column 9, line 28, strike out the Words and a rotatable driving member; and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Olce. Signed and sealed this 3rd day of October, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant ommz'ssz'oner of Patents. 

